struct buf;
struct context;
struct file;
struct inode;
struct pipe;
struct proc;
struct spinlock;
struct sleeplock;
struct stat;
struct superblock;

// bio.c
void binit(void);
struct buf *bread(uint, uint);
void brelse(struct buf *);
void bwrite(struct buf *);
void bpin(struct buf *);
void bunpin(struct buf *);

// console.c
void consoleinit(void);
void consoleintr(int);
void consputc(int);

// exec.c
int exec(char *, char **);

// file.c
struct file *filealloc(void);
void fileclose(struct file *);
struct file *filedup(struct file *);
void fileinit(void);
int fileread(struct file *, uint64, int n);
int filestat(struct file *, uint64 addr);
int filewrite(struct file *, uint64, int n);

// fs.c
void fsinit(int);
int dirlink(struct inode *, char *, uint);
struct inode *dirlookup(struct inode *, char *, uint *);
struct inode *ialloc(uint, short);
struct inode *idup(struct inode *);
void iinit();
void ilock(struct inode *);
void iput(struct inode *);
void iunlock(struct inode *);
void iunlockput(struct inode *);
void iupdate(struct inode *);
int namecmp(const char *, const char *);
struct inode *namei(char *);
struct inode *nameiparent(char *, char *);
int readi(struct inode *, int, uint64, uint, uint);
void stati(struct inode *, struct stat *);
int writei(struct inode *, int, uint64, uint, uint);

// ramdisk.c
void ramdiskinit(void);
void ramdiskintr(void);
void ramdiskrw(struct buf *);

// kalloc.c
void *kalloc(void);
void kfree(void *);
void kinit();
void incref(uint64);

int get_free_mem(void);

// log.c
void initlog(int, struct superblock *);
void log_write(struct buf *);
void begin_op(int);
void end_op(int);
void crash_op(int, int);

// pipe.c
int pipealloc(struct file **, struct file **);
void pipeclose(struct pipe *, int);
int piperead(struct pipe *, uint64, int);
int pipewrite(struct pipe *, uint64, int);

// printf.c
void printf(char *, ...);
void panic(char *) __attribute__((noreturn));
void printfinit(void);

// proc.c
int cpuid(void);
void exit(int);
int fork(void);
int growproc(int);
pagetable_t proc_pagetable(struct proc *);
void proc_freepagetable(pagetable_t, uint64);
int kill(int);
struct cpu *mycpu(void);
struct cpu *getmycpu(void);
struct proc *myproc();
void procinit(void);
void scheduler(void) __attribute__((noreturn));
void sched(void);
void setproc(struct proc *);
void sleep(void *, struct spinlock *);
void userinit(void);
int wait(uint64);
void wakeup(void *);
void yield(void);
int either_copyout(int user_dst, uint64 dst, void *src, uint64 len);
int either_copyin(void *dst, int user_src, uint64 src, uint64 len);
void procdump(void);

int get_proc_unused(void);
// swtch.S
void swtch(struct context *, struct context *);

// spinlock.c
void acquire(struct spinlock *);
int holding(struct spinlock *);
void initlock(struct spinlock *, char *);
void release(struct spinlock *);
void push_off(void);
void pop_off(void);
uint64 sys_ntas(void);

// sleeplock.c
void acquiresleep(struct sleeplock *);
void releasesleep(struct sleeplock *);
int holdingsleep(struct sleeplock *);
void initsleeplock(struct sleeplock *, char *);

// string.c
int memcmp(const void *, const void *, uint);
void *memmove(void *, const void *, uint);
void *memset(void *, int, uint);
char *safestrcpy(char *, const char *, int);
int strlen(const char *);
int strncmp(const char *, const char *, uint);
char *strncpy(char *, const char *, int);

// syscall.c
int argint(int, int *);
int argstr(int, char *, int);
int argaddr(int, uint64 *);
int fetchstr(uint64, char *, int);
int fetchaddr(uint64, uint64 *);
void syscall();

// trap.c
extern uint ticks;
void trapinit(void);
void trapinithart(void);
extern struct spinlock tickslock;
void usertrapret(void);
int cowfault(pagetable_t pagetable, uint64 va);

// uart.c
void uartinit(void);
void uartintr(void);
void uartputc(int);
int uartgetc(void);

// vm.c
void kvminit(void);
void kvminithart(void);
uint64 kvmpa(uint64);
void kvmmap(uint64, uint64, uint64, int);
int mappages(pagetable_t, uint64, uint64, uint64, int);
pagetable_t uvmcreate(void);
void uvminit(pagetable_t, uchar *, uint);
uint64 uvmalloc(pagetable_t, uint64, uint64);
uint64 uvmdealloc(pagetable_t, uint64, uint64);
int uvmcopy(pagetable_t, pagetable_t, uint64);
void uvmfree(pagetable_t, uint64);
void uvmunmap(pagetable_t, uint64, uint64, int);
void uvmclear(pagetable_t, uint64);
pte_t *walk(pagetable_t pagetable, uint64 va, int alloc);
uint64 walkaddr(pagetable_t, uint64);
int copyout(pagetable_t, uint64, char *, uint64);
int copyin(pagetable_t, char *, uint64, uint64);
int copyinstr(pagetable_t, char *, uint64, uint64);
void vmprint(pagetable_t);
void pgaccess(uint64 *, uint64, uint64 *);

// plic.c
void plicinit(void);
void plicinithart(void);
int plic_claim(void);
void plic_complete(int);

// virtio_disk.c
void virtio_disk_init(int);
void virtio_disk_rw(int, struct buf *, int);
void virtio_disk_intr(int);

// number of elements in fixed-size array
#define NELEM(x) (sizeof(x) / sizeof((x)[0]))

// Extra files for allocator lab

// buddy.c
void bd_init(void *, void *);
void bd_free(void *);
void *bd_malloc(uint64);

struct list
{
  struct list *next;
  struct list *prev;
};

// list.c
void lst_init(struct list *);
void lst_remove(struct list *);
void lst_push(struct list *, void *);
void *lst_pop(struct list *);
void lst_print(struct list *);
int lst_empty(struct list *);
